Implantable medical devices such as pacemakers, defibrillators, speech processors, left ventricular assist devices (LVAD), and neurostimulators have many stringent requirements. They must be small and lightweight for ease of implant and patient comfort. Likewise, batteries for use in the aerospace industry are required to be lightweight and have a long calendar life.
One of the problems with prior art batteries is that the calendar life is too short. This can be attributed to several mechanisms, for example, decomposition of the PVdF binder, Li deposition, and electrolyte decomposition.